In 21 century, display filed is dominated by flat panel display. Thin film transistor liquid crystal display (TFT-LCD) has the advantages of small volume, low energy consumption, low radiation, and etc., and thus prevails in the flat panel display market. Array substrate and manufacturing process thereof are key factors for determining the performance, yield and price of the TFT-LCD.
With the developments of the liquid crystal display panel towards large-size, high-resolution, high-frequency, three-dimensional view and active matrix organic light emitting diode (AMOLED), oxide semiconductor material with high carrier mobility has drawn great attentions. Oxide semiconductor material has good compatibility with apparatuses for manufacturing conventional TFT-LCD without the necessity of transforming these apparatuses, and thus oxide semiconductor material has an obvious advantage in mass production. However, when oxide semiconductor material is used as active layer and metal material is used as source and drain electrodes, oxide semiconductor material in channel region is damaged because enchant for etching the metal material damages the oxide semiconductor material, and thus performance of the thin film transistor is deteriorated.
In order to improve the stability of the TFT, the respective layers of the TFT are sequentially prepared by mask processes (mask photolithographic processes), and an etch stop layer is provided on the semiconductor active layer to secure the performance of the TFT. Accordingly, an additional mask process is added to the conventional process. In this case, the cost may be increased and it may be difficult to secure the product quality due to high cost and high complexity of the mask process.